Truck loses cargo question

I was hoping some one could help me by giving an equation on how to do this question, I can't seem to find one for it in my notes :/

A box of mass 11.3kg rests on the flat floor of a truck. The coefficients of friction between the box and floor are Us= 0.18 and Uk= 0.16. The truck stops at a stop sign and then starts to move with an acceleration of 2.16m/s/s
If the box is a distance 1.75m from the rear of the truck when the truck starts, how much time elapses before the box falls off the truck?